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| author | Helge Deller <deller@parisc-linux.org> | 2006-01-13 13:21:06 -0700 |
|---|---|---|
| committer | Kyle McMartin <kyle@duet.int.mcmartin.ca> | 2006-01-22 20:26:54 -0500 |
| commit | 1bcdd8548286743e1d6b3d53c96a90c6da975620 (patch) | |
| tree | b244aa416992bbd06c4153ec2c97022629826ef2 /arch | |
| parent | a2bb214dcd1db862fdb6421e21f1cff0c3535162 (diff) | |
| download | linux-1bcdd8548286743e1d6b3d53c96a90c6da975620.tar.gz linux-1bcdd8548286743e1d6b3d53c96a90c6da975620.tar.bz2 linux-1bcdd8548286743e1d6b3d53c96a90c6da975620.zip | |
[PARISC] Add CONFIG_DEBUG_RODATA to protect read-only data
Add the parisc version of the "mark rodata section read only" patches.
Based on code from and Signed-off-by Arjan van de Ven
<arjan@infradead.org>, Ingo Molnar <mingo@elte.hu>, Andi Kleen <ak@muc.de>,
Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>.
Signed-off-by: Helge Deller <deller@parisc-linux.org>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/parisc/Kconfig.debug | 10 | ||||
| -rw-r--r-- | arch/parisc/hpux/entry_hpux.S | 3 | ||||
| -rw-r--r-- | arch/parisc/kernel/syscall.S | 2 | ||||
| -rw-r--r-- | arch/parisc/mm/init.c | 15 |
4 files changed, 27 insertions, 3 deletions
diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug index 8caaed187a1f..9166bd117267 100644 --- a/arch/parisc/Kconfig.debug +++ b/arch/parisc/Kconfig.debug @@ -11,4 +11,14 @@ config DEBUG_RWLOCK too many attempts. If you suspect a rwlock problem or a kernel hacker asks for this option then say Y. Otherwise say N. +config DEBUG_RODATA + bool "Write protect kernel read-only data structures" + depends on DEBUG_KERNEL + help + Mark the kernel read-only data as write-protected in the pagetables, + in order to catch accidental (and incorrect) writes to such const + data. This option may have a slight performance impact because a + portion of the kernel code won't be covered by a TLB anymore. + If in doubt, say "N". + endmenu diff --git a/arch/parisc/hpux/entry_hpux.S b/arch/parisc/hpux/entry_hpux.S index fa9bf38787e7..31c8cccfba31 100644 --- a/arch/parisc/hpux/entry_hpux.S +++ b/arch/parisc/hpux/entry_hpux.S @@ -22,10 +22,9 @@ #include <linux/linkage.h> #include <asm/unistd.h> - .text - #define ENTRY_NAME(_name_) .word _name_ + .section .rodata,"a" .align 4 .export hpux_call_table .import hpux_unimplemented_wrapper diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S index d66163492890..af88afef41bd 100644 --- a/arch/parisc/kernel/syscall.S +++ b/arch/parisc/kernel/syscall.S @@ -650,6 +650,8 @@ end_linux_gateway_page: #define LWS_ENTRY(_name_) .word (lws_##_name_ - linux_gateway_page) #endif + .section .rodata,"a" + .align 4096 /* Light-weight-syscall table */ /* Start of lws table. */ diff --git a/arch/parisc/mm/init.c b/arch/parisc/mm/init.c index 9999eb045238..6f36d0b17d9e 100644 --- a/arch/parisc/mm/init.c +++ b/arch/parisc/mm/init.c @@ -417,6 +417,19 @@ void free_initmem(void) #endif } + +#ifdef CONFIG_DEBUG_RODATA +void mark_rodata_ro(void) +{ + extern char __start_rodata, __end_rodata; + /* rodata memory was already mapped with KERNEL_RO access rights by + pagetable_init() and map_pages(). No need to do additional stuff here */ + printk (KERN_INFO "Write protecting the kernel read-only data: %luk\n", + (unsigned long)(&__end_rodata - &__start_rodata) >> 10); +} +#endif + + /* * Just an arbitrary offset to serve as a "hole" between mapping areas * (between top of physical memory and a potential pcxl dma mapping @@ -685,7 +698,7 @@ static void __init pagetable_init(void) #ifdef CONFIG_BLK_DEV_INITRD if (initrd_end && initrd_end > mem_limit) { - printk("initrd: mapping %08lx-%08lx\n", initrd_start, initrd_end); + printk(KERN_INFO "initrd: mapping %08lx-%08lx\n", initrd_start, initrd_end); map_pages(initrd_start, __pa(initrd_start), initrd_end - initrd_start, PAGE_KERNEL); } |